This invention generally relates to a gas turbine engine, and more particularly to a slider seal assembly for a gas turbine engine.
In an aircraft gas turbine engine, such as a turbofan engine, air is pressurized in a compressor and mixed with fuel in a combustor for generating hot combustion gases. The hot combustion gases flow downstream through turbine stages which extract energy from the gases. In a two spool gas turbine engine, a high pressure turbine powers a high pressure compressor, while a low pressure turbine powers a fan section disposed upstream of the compressor and a low pressure compressor.
Combustion gases are discharged from the turbofan engine through a core exhaust nozzle and fan air is discharged through an annular fan exhaust nozzle defined at least partially by a nacelle surrounding the core engine. A majority of propulsion thrust is provided by the pressurized fan air which is discharged through the fan exhaust nozzle, while the remaining thrust is provided from the combustion gases discharged through the core exhaust nozzle.
The core engine components, including the compressor, the combustor and the turbine, are surrounded by a cylindrical outer casing. A multitude of interface parts, such as borescope plugs, are received within openings of the outer casing and provide access points for inspecting the internal components of the core engine. The interface parts are removable to access the interior of the core engine. For example, fiber optics equipment may be inserted into an opening of the outer casing upon removal of a borescope plug to detect debris, cracking or other damage to the interior components of the gas turbine engine.
Additionally, gas turbines engines may include numerous other interface parts, such as fuel fittings, customer bleed ports and the like. Seal assemblies are required to seal the interface between the interface parts and the openings of the outer casing. That is, the seal assemblies reduce airflow leakage between the interface parts and the outer casing as airflow is communicated within the core engine during engine operation.
The seal assemblies typically include a housing and a metallic seal plate, such as a titanium seal plate. The housing is mounted to the outer casing, the seal plate is affixed adjacent to the housing, and the interface part extends through openings of the seal plate and the housing to provide a seal therebetween. The opening of the seal plate must be machined or drilled at an angle to compensate for the curvature of the outer casing.
Disadvantageously, interface parts may experience heavy wear near the contact area between the interface part and the seal plate due to the metallic nature of the seal plate and the angle at which the interface parts extend through the seal plate. The heavy wear at this contact area may result in airflow leakage between the core airflow passage and the fan bypass airflow passage of the gas turbine engine. Increased wear at the interface between the seal assemblies and the interface parts may be furthered by thermal growth mismatch. This is caused by the severe temperature differences the engine experiences between the core airflow passage and the fan bypass airflow passage, which may cause displacement of the interface parts relative to the seal plates.
Accordingly, it is desirable to provide an effective slider seal assembly that reduces wear and reduces airflow leakage between the core airflow passage and the fan bypass airflow passage of a gas turbine engine.